Fix invalid usage of Math.floor + simplify code

First:
Math.floor(3.2) -> 3
Math.floor(3.7) -> 3
Math.floor(-3.7) -> -4
Math.floor(-3.2) -> -4

Second:
3.2|0  -> 3
-3.2|0 -> -3

So, behaviour of these approaches are DIFFERENT on negative values. So:
http://stackoverflow.com/questions/596467/how-do-i-convert-a-number-to-an-integer-in-javascript

src/analyzer.c: simplified code.
src/library.js:
* Simplify code, potentially fix bugs with negative time values in many places.
* FIX bugs in handling of negative numbers in modf(), modff() and div()

Simplify code for other functions where we need integer part of floating-point number.
Support for array attributes in WebIDL bindings.
Bounds-checking for array attributes.
Embind: Allow the cloning of pointers scheduled for deletion
Embind: support nulls in embind_repr()
Update the simd.js

It is based on version https://github.com/johnmccutchan/ecmascript_simd/blob/14aa231d3c1021695ecee467ef35e5d61c8c669e/src/ecmascript_simd.js

Changes:
46620fd Add type check into SIMD operations.
1f29859 Fix float64x2.clamp implementation and add test case for it.
22b8ccf Use object properties instead of typed array as storage in polyfill
8941215 Changed conversion operators from SIMD.XXX.toYYY() to SIMD.YYY.fromXXX(), added 'select' operator for all types, added/updated tests
3eaaf69 Added reciprocal, reciprocalSqrt, shuffle, shuffleMix, comparison, and select operators to SIMD.float64x2
6f68238 Added SIMD.float64x2 (abs, neg, add, sub, mul, div, clamp, min, max, scale, sqrt, withX, withY, SIMD.float32x4.toFloat64x2)
Update SIMD.js code generation due to API update.
disable test_readdir in non-emcc
limit the size of the test runner library cache name, to avoid OS limits
update sockets.test_nodejs_sockets_echo
benchmark runner fixes
Merge pull request #2690 from waywardmonkeys/upstream-embind-changes

Upstream embind changes
Add .ico files to site
Fixes to building from source on Windows. Updated introduction. Minor updates to many other files
Make Talks and Publications topic done (not ready for review)
faq updates
Merge pull request #2686 from artillery/webidl-array-attributes

WebIDL: array attribute bindings
Update filesystem API with clarifications from Anthony Pesch. Mark AboutEmscription doc as ready-for-review
Conversion of emcc docs to form that can easily be converted to text. Full review of that doc.
Fixes to fonts and some text as result of final review by Jukka on a number of docs